$resultado = htmlentities(htmlspecialchars($entrada));

<?php
/* Check constants */
if(!defined('KERNELBASE')) trigger_error("KERNELBASE not defined.", E_USER_ERROR);
if(!defined('SELFLOC')) trigger_error("SELFLOC not defined.", E_USER_ERROR);

/* Include base API */
require_once(KERNELBASE.'core/Base.php');
require_once(KERNELBASE.'core/Library.php');
require_once(KERNELBASE.'core/KernelException.php');

/* Core class */
class TWS_Core extends TWS_Base
{
	private $objects = array();
	public $config;

	/* Default constructor */
	public function __construct()
	{
		/* Call TWS_Base constructor */
		parent::__construct('TWS_Core');
		
		/* Define kernel constants */
		define('KERNELVERSION', '3.0');
		define('KERNELSTATUS', '1');
	}

	private function __get($prop)
	{
		if(isset($this->objects[$prop]))
		{
			return $this->objects[$prop];
		} else {
			throw new KernelException("TWS_Core::__get", "Attemp to read from undefined property($prop).");
		}
	}

	private function __set($prop, $value)
	{
		if(isset($this->objects[$prop]))
		{
			return $this->objects[$prop];
		} else {
			throw new KernelException("TWS_Core::__set", "Attemp to write to undefined property($prop).");
		}
	}

	private function __isset($prop)
	{
			return isset($this->objects[$prop]);
	}

	private function __unset($prop)
	{
		if(isset($this->objects[$prop]))
		{
			unset($this->objects[$prop]);
		} else {
			throw new KernelException("TWS_Core::__unset", "Attemp to delete undefined property($prop).");
		}
	}
	
	/* Kernel start-up routine */
	public final function core_start()
	{
		/* Disable magic quotes */
		set_magic_quotes_runtime(0);

		/* Load config */
		include(KERNELBASE.'config/core.conf.php');
		$this->config = $core;

		/* Load DataBaseEngine */
		try {
			$this->load_library('DataBaseEngine');

			/* Start database engine */
			$this->db->start_engine();

			/* Load the other basic libraries */
			$this->load_library('LoadableModule');
			$this->load_library('LoadableTemplate');
			$this->load_library('DynamicMenu');
		} catch(KernelException $e) {
			$e->printKernelPanic();
			die();
		}
	}

	public final function load_library($class, $instantiate = true)
	{
		if (isset($this->objects[$class]))
		{
			return;
		}
		
		if (file_exists(KERNELBASE.'core-libs/'.$class.'.lib.php'))
		{
			require(KERNELBASE.'core-libs/'.$class.'.lib.php');	
		}
		else
		{
			if (file_exists(KERNELBASE.'libs/'.$class.'.lib.php'))
			{
				require(KERNELBASE.'libs/'.$class.'.lib.php');
			}
			else
			{
				throw new KernelException("TWS_Core::load_library", "Can't load the requested library(".$class."). The library doesn't exists.");
				return;
			}
		}

		if ($instantiate)
		{
			$class_name = 'TWS_'.$class;
			if(class_exists($class_name))
			{
				$tmp =& new $class_name(&$this);
				$this->objects[$tmp->get_kernel_var()] = $tmp;
			} else {
				throw new KernelException("TWS_Core::load_library", "Can't load the requested library(".$class."). The library is corrupted.");
			}
		}
		return;
	}

	public final function get_loaded_libraries()
	{
		return $this->objects;
	}

	public final function install_library($location)
	{
		if(file_exists($location))
		{
			copy($location, KERNELBASE.'libs/');
		}
		return;
	}

	public final function uninstall_library($name)
	{
		if(file_exists(KERNELBASE.'libs/'.$name.'.lib.php'))
			unlink(KERNELBASE.'libs/'.$name.'.lib.php');
	}
}
?>

$core->nombre_libreria

$core->load_library("LoadableModule");

$core->modules->add_module($module_descriptor);

if ($instantiate)
{
	$class_name = 'TWS_'.$class;
	if(class_exists($class_name))
	{
		$this->objects[$class] =& new $class_name();
		$kernel_var = $this->objects[$class]->get_kernel_var();
		$this->$kernel_var = $this->objects[$class]; // ACA es el error!
	} else {
		trigger_error("Kernel panic: Can't load the requested library(".$class."). The library is corrupted.", E_USER_ERROR);
	}
}